Too Much Fish Oil Might Boost Prostate Cancer Risk

WEDNESDAY, July 10 (HealthDay News) -- Eating a lot of oily fish or taking potent fish oilsupplements may increase a man's risk of developing prostate cancer, new research suggests.

Moreover, marine sources of omega-3 fatty acids may also raise the risk for aggressive prostate cancer, according to the study by scientists at the Fred Hutchinson Cancer Research Center in Seattle.

"These anti-inflammatory omega-3s were associated with a 43 percent increased risk for prostate cancer overall, and a 71 percent increased risk in aggressive prostate cancer," said study lead author Theodore Brasky, a research assistant professor at Ohio State University Comprehensive Cancer Center in Columbus, who was at Hutchinson at the time of the study.

Omega-3 fatty acids, found in fish such as salmon, trout and fresh tuna and in fish oil capsules, are widely reputed to have health benefits because of their anti-inflammatory properties.

But this new research, published online July 11 in the Journal of the National Cancer Institute, confirms damaging evidence reported in two prior studies.

Just why are these omega-3 fatty acids associated with prostate cancer? "That's the million dollar question," Brasky said.

Omega-3 fatty acids may have properties that aren't well understood and in high doses could cause oxidative stress, which can lead to DNA damage, possibly increasing the risk for prostate cancer, he speculated.

Oxidative stress plays a role in other cancers, Brasky said.

Although omega-3 fatty acids have been touted as beneficial to heart patients, results of a study published May 9 in the New England Journal of Medicine found they didn't live up to the claims.

"These fatty acids have been promoted as a blanket anti-chronic disease fatty acid," Brasky noted. "But nutrition is more nuanced, as is disease occurrence. It's about time we stop talking about foods as good or bad and no gray area," he said.